Update cargo inline with 2018-04-07 nightly

[alexheretic]

git shortlog 311a5..b70ab

Aleksey Kladov (17):
      Supply units to the context at the point of creation
      Introduce compilation files
      Restore --features args for cargo rustdoc
      Slightly better variable names
      Replace a triple with a struct for readability
      Extract target info
      Make TargetInfo.cfg private
      Rename TargetFileType -> FileFlavor
      Move filename logic to FileType
      Replace triple with struct
      Make assertion more informative
      Implement `--out-dir` option
      Feature gate `--out-dir`
      Test out-dir edge cases
      Replace home-grown create_dir_all with std::fs::create_dir_all
      Fix tests for mac
      Slightly improve InternedString

Alex Crichton (3):
      Run `rustc` for information fewer times
      Remove rustfmt from Travis
      Less aggressively poison sources on builds

Bastien Orivel (1):
      Replace tempdir by tempfile

Dirkjan Ochtman (7):
      Fix formatting issues with cargo fmt
      Move resolver::Resolve into a new resolver::resolve module
      Move utility types from resolver into resolver::types
      Move resolver::Context into new resolver::context module
      Move resolver Context initialization into a method
      Reorder code in resolver module for better readability
      Fix spelling errors in interning module

Eric Huss (1):
      locate-project: Fix help description.

Klaus Purer (4):
      docs(Z-flags): Add description for each -Z flag in cargo -Z help
      tests(help): Add test for -Z help output
      tests(help): Fix assertion by using the full line text
      chore(cli): Remove dead code in main()

Kurtis Nusbaum (1):
      rename epoch to edition

Mark Simulacrum (1):
      Remove thread local, replacing with DeserializeSeed

Orestis Floros (1):
      cargo_new: remove redundant leading new lines from ignore files

Philipp Oppermann (2):
      Canonicalize paths passed as `--target`
      Add custom target tests

gibix (5):
      fix #2773 with new precise encode
      cargo fmt
      fix typo , drop return and intermediate vector
      cargo fmt
      add precise test

rleungx (2):
      tweak error message
      address comment

[nrc]

Thanks!